1. Field of the Invention
The invention relates to infrared (IR) absorption. In particular, this invention relates to dithiene complexes of bivalent transition metals which exhibits infrared absorption characteristics. More specifically, this invention relates to the synthesis of symmetrical transition metal dithiene compounds.
2. Description of the Prior Art
The synthesis of symmetrical and asymmetrical transition metal dithiene compounds are known in the art. A general method of preparing these compounds is disclosed in the article "Picosecond Flash Photolysis and Spectroscopy: Bis-(4-Dimethylaminodithiobenzil) Ni(II), BDN," Chemical Physics Letters, Magdi, et al., Vol 28, No. 2, Sept. 15, 1974, pp. 263-269. In addition U.S. Pat. Nos. 3,894,069; 3,743,964 and 3,588,216, disclose the preparation of dithiol metal complexes in yields of from about 10 percent to about 17 percent. However, these references do not disclose the synthesis of the compounds forming the basis of the present invention.